Super Mario Bros is one of 20 NES games that will be available for free on the service, with new online features added. Other games at launch include The Legend of Zelda, Donkey Kong and Balloon Fight. More are to be added over time. Switch Online also allows online play through modern Switch games such as Splatoon 2 and Mario Kart 8 Deluxe, of course.

The service is limited when compared to Sony and Microsoft's well established online subscriptions, and doesn't include voice chat for example. For that, you need to use an external app on your cellphone or tablet. It does offer cloud saves, however.

Nintendo is hoping that the low price of Switch Online will make the difference - one month costs £3.99, six months is $7.99 while a full year is $19.99. A Family Plan is available for $34.99, allowing up to seven users to share a Switch Online account.

An exact date for Switch Online's launch has yet to be announced, but it will be available by the end of September.